Sealing material for ant groove

ABSTRACT

There is disclosed a sealing material for an ant groove, wherein the sealing material is easy to fit to the ant groove and little involves a phenomenon such that the sealing material unfavorably slips out of the ant groove in the form of remaining fixing to the opposite member when the sealed place is opened, and wherein the sealing material can exercise the good sealing function. The sectional shape of the sealing material has: a straight bottom edge  34  which is disposed on a bottom face of the ant groove  12 ; an arched convex edge  31  which contacts with the other member  20 ; a first projecting edge  33  which projects outside; a concave inlet portion  39 ; a second projecting edge which is composed of straight lines  35, 36  that project outside; a straight sloping edge  38 ; and at least one corner portion  37   a - c  which is constituted in the range of from the straight bottom edge  34  via the second projecting edge  35, 36  to the sloping edge  38.

This application is the National Stage of International Application No.PCT/JP04/04323, filed Mar. 26, 2004, which was published in English asInternational Patent Publication WO 2004/092619 A1 on Oct. 28, 2004,which is entitled to the right of priority of Japanese PatentApplication 2003-109446, filed Apr. 14, 2003.

TECHNICAL FIELD

The present invention relates to a sealing material for an ant groove.In detail, what the present invention is to provide is a sealingmaterial used for sealing a joint place between members by being fittedto the joint place in such as vacuum apparatus and piping instruments towhich high airtightness is demanded.

BACKGROUND ART

There are known arts in which an ant groove having a trapezoidalsectional shape is utilized as a sealing structure in a sealed placerequired to have airtightness.

The ant groove structure has a merit such that the fitted sealingmaterial little falls off. The ant groove structure is assumed to be astructure suitable for such as gate valves which repeat their openingand closing.

There are proposed various arts of improving the shape or structure ofthe sealing material in order to enhance performances such asairtightness as to the above sealing structure which utilizes the antgroove.

Patent document 1 proposes a sealing material for an ant groove whereinthe sealing material is approximately in the shape of a teardrop suchthat a larger arched portion and a smaller arched portion are connectedtogether through a straight edge. The fitting is facilitated by pressingfirst the smaller arched portion of the sealing material into the antgroove. In a fitted state, it is assumed that: one straight edgecontacts with a bottom face of the ant groove, and the smaller archedportion fits into an inner corner at one side of the ant groove, andanother straight edge contacts with an inner sloping face of the antgroove, whereby the sealing material is disposed in a stable state, sothat there occurs little twisting.

Patent document 2 relating to a patent application previously made bythe applicant of the present patent application discloses a sealingmaterial for an ant groove wherein the sealing material comprises:circular-arc-shaped projecting portions which project in threedirections; and concave inlet portions, each of which is located betweenthe projecting portions. When fitted to the ant groove, this sealingmaterial for an ant groove can be passed comparatively easily through anarrow opening of the ant groove by pressing the oppositecircular-arc-shaped projecting portion side of the sealing material intothe ant groove, with one concave inlet portion of the sealing materialas the base point in a state where this concave inlet portion isdisposed on an opening edge of the ant groove. In a state where thesealing material is fitted to the ant groove, a pair ofcircular-arc-shaped projecting portions disposed in a bilaterallysymmetrical shape contact with the bottom face of the ant groove and, inthe center, the remaining one circular-arc-shaped projecting portioncontacts with a member facing the ant groove, whereby the good elasticdeformation or sealing function can be performed.

[Patent Document 1]

-   -   JP-A-510286/1997 (Kohyo)

[Patent Document 2]

-   -   JP-A-130481/2002 (Kokai)

The aforementioned prior arts also have problems such that: the fittingto the ant groove is difficult to carry out, or the falling off from theant groove tends to occur.

In the art of the patent document 1, after the teardrop-shaped sealingmaterial for an ant groove has been inserted into the ant groove withthe smaller arched portion of the sealing material down, the smallerarched portion must be pressed into the inner corner at one side of theant groove in a way that the entirety of the sealing material istwisted. The motion of properly twisting the entirety of the sealingmaterial for the ant groove in the narrow ant groove is difficult, andthe fitting has directionality. Therefore, misfitting tends to becaused. From above the ant groove, it cannot be checked whether thesmaller arched portion has surely be disposed into the inner corner atone side or not. Thus, there is a worry that the use is made with thefitting left insufficient. In addition, the occupation ratio of thesealing material to the ant groove is so small that, in the case wherecompressed repeatedly, the sealing material repeats its contact with theinner wall surface of the ant groove and therefore tends to generateparticles due to friction.

As to the art of the patent document 2, the fitting to the ant groove iseasier than that of the teardrop-shaped sealing material of the patentdocument 1. However, the motion of gyratorily pressing the oppositecircular-arc-shaped projecting portion side into the ant groove, withthe aforementioned concave inlet portion as the base point, needs greatforce. Its reason can be considered to be that, unless the entirety ofthe circular-arc-shaped projecting portion is elastically deformed, thesealing material cannot be passed through the opening of the ant groove.When an attempt is made to release the sealing made with the sealingmaterial for an ant groove, such as when a motion of opening a gatevalve is made, there occurs a phenomenon such that the sealing materialfor an ant groove unfavorably slips out of the ant groove in the form ofhaving attached to the opposite member. This fixation phenomenon is aphenomenon which greatly occurs between a sealing material (e.g. rubber)and a metal member when the sealing material is applied to such as agate valve of a semiconductor production apparatus, to the sealed placeof which a fixation-preventing means such as greasing or coating cannotbe applied. The concave inlet portions, which are disposed in positionsbilaterally symmetrical as to the concave inlet portion that is utilizedas the base point during the fitting, do not take part in the fittingfunction. Therefore, there is a possibility that the elastic repulsiveforce or sealing function of the sealing material for an ant groove maybe spoiled correspondingly to the presence of the concave inlet portionsin three places.

DISCLOSURE OF THE INVENTION Object of the Invention

An object of the present invention is to provide a sealing material foran ant groove, wherein the sealing material is easy to fit to the antgroove, and can exercise the good sealing function, and little involvesthe phenomenon such that the sealing material unfavorably slips out ofthe ant groove in the form of remaining fixing to the opposite memberwhen the sealed place is opened.

SUMMARY OF THE INVENTION

A sealing material according to the present invention for an ant grooveis a sealing material for an ant groove, which is fitted to the antgroove made in a surface of either one of members in a joint placebetween these members and contacts with a surface of the other member,thereby sealing both the members, with the sealing material comprising:an elastically deformable material; and a sectional shape having: astraight bottom edge which is disposed on a bottom face of said antgroove; an arched convex edge which contacts with the surface of saidother member facing said ant groove; a first projecting edge whichconnects with one end of said bottom edge and projects outside; aconcave inlet portion which is located between said first projectingedge and said arched convex edge; a second projecting edge whichconnects with the other end of said straight bottom edge and is composedof straight lines that project outside; a straight sloping edge of whichone end connects with the opposite end of said arched convex edge as tosaid first projecting edge and of which the other end connects with saidsecond projecting edge; and at least one corner portion which isconstituted in the range of from said straight bottom edge via saidsecond projecting edge to said sloping edge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a sealing material for an ant groove in afitted state, illustrating a mode for carrying out the presentinvention.

FIG. 2 is an outline view illustrating the sectional shape and size ofthe sealing material for an ant groove.

FIG. 3 is a motion-explaining view illustrating the operation of fittingthe sealing material for an ant groove.

FIG. 4 is a sectional view of a misfitted state.

FIG. 5 is a sectional view of a sealed state.

FIG. 6 is a graphic view of contact face pressure distributions in thesealed state.

FIG. 7 is a sectional view during the motion of releasing the sealing.

FIG. 8 is a sectional view illustrating a modified mode of the sectionalshape.

FIG. 9 is a plan view during the fitting to a sealing plate.

FIG. 10 is a sectional view of the same as the above.

EXPLANATION OF THE SYMBOLS

10: Member with ant groove formed therein

12: Ant groove

20: Opposite member

30: Sealing material for ant groove

31: Arched convex edge

32: Vertical edge

33: First projecting edge

34: Straight bottom edge

35, 36: Second projecting edge (straight edges)

37 a to 37 c: Corner portions

38: Sloping edge

39: Concave inlet portion

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, detailed descriptions are given about the sealing materialaccording to the present invention for an ant groove. However, the scopeof the present invention is not bound to these descriptions. And otherthan the following illustrations can also be carried out in the form ofappropriate modifications of the following illustrations within thescope not departing from the spirit of the present invention.

[Joint Place]:

The sealing material is used in order that a joint place, where a pairof members are joined together face to face in various machinery andapparatus, can be sealed with high airtightness maintained. A structureportion to which such a sealing function is demanded would notespecially be limited as to such as structure or shape of the membersconstituting the joint place.

Examples of the joint place to which the high airtightness is demandedinclude: a joint place between a chamber main body and an opening andshutting lid in a treatment chamber which is used in processes forproduction of semiconductors and liquid crystals; and a portion to whicha gate valve that is free to open and close and is equipped to the abovetreatment chamber is furnished; and besides, a place where an openingand shutting lid or an attached instrument is furnished to such asvacuum apparatus; and a joint place of a piping instrument.Particularly, the sealing material is suitable for a place where thesealing material tends to fix to a metal member. Specifically, thesealing material is suitable for: uses to which the fixation-preventingmeans by greasing or coating cannot be applied; and a place where thefixation tends to make progress due to such as heat or contacting withgas.

In any case, in the joint place, a pair of members face each other, andthe ant groove is made in a surface of one of the members, and thesealing material is fitted to this ant groove. The surface of the othermember may be a mere flat face or, as the case may be, a shallow grooveor difference in level is made in a place corresponding to the antgroove.

[Ant Groove]:

The basic sectional structure of the ant groove is approximately in theshape of a trapezoid of which the width on the inner side is larger thanthat on the opening side.

The bottom face of the ant groove can be a flat face parallel to theopening. Both side faces of the ant groove can be sloping-faces whichslope inward from the bottom side toward the opening side. Both sidefaces may differ in sloping angle. A side face may be a curved face. Acorner portion where a side face and the bottom face cross each other,or an inner edge of the opening, can be provided with acircular-arc-shaped R. (roundness) or rounded off.

The ant groove is disposed in a ring shape so as to enclose a regionwhich must be sealed in the aforementioned joint place. For example, theant groove is disposed in a ring shape so as to enclose an outerperiphery of such as a vacuum space or a passageway of a fluid. As tothe disposition shape of the ant groove, besides the circular shape,other shapes such as a regular oval shape, a long oval shape, arectangular shape, and a polygonal shape can be set appropriately forthe shape of the sealed place.

In the joint place, either of a pair of members may be provided with theant groove. For example, the ant groove can be made in a bottom face ofa lid which opens and shuts upward and downward.

[Sealing Material for Ant Groove]:

Techniques common to conventional O-rings and other sealing materialsfor an ant groove can be adopted for the constituting material and basicstructure of the sealing material for an ant groove.

Natural or synthetic rubber materials and elastic resin materials areusable as the constituting material of the sealing material if they areelastic materials capable of elastic deformation which is demanded ofthe sealing function. Specific examples thereof include fluororubbers,silicone rubbers, and EPDM type rubbers. More specifically, it ispossible to select materials appropriate for conditions of environmentsunder which the sealing is carried out (conditions such as kinds,temperature, and pressure of fluids). For example, under corrosiveenvironments (such as under various plasma conditions) in the field ofthe semiconductor production technique, the fluororubbers are favorable.In the case where the sealing material is used in an opening andshutting lid place of a drying chamber, there are preferred the EPDMtype rubbers, because they are excellent in the chemical resistance andthe clean property, and further, take low costs.

The basic structure of the sealing material is a ring-shaped structure,that is, a ring, having the specific sectional shape. The ring diameterand ring disposition shape of the sealing material is set so as toconform to the ring diameter and disposition shape of the ant groove towhich the sealing material is fitted.

The sectional shape of the sealing material has a straight bottom edge,an arched convex edge, a first projecting edge, a concave inlet portion,a second projecting edge, a sloping edge, and a corner portion. Theapproximate shape of the entirety is a shape such that a heart shape isput in an inclined state on a flat face (which may hereinafter bereferred to as “inclined heart shape”).

<Straight Bottom Edge>:

When the sealing material is fitted to the ant groove, the straightbottom edge is disposed on the bottom face of the ant groove. Even in astate where the straight bottom edge is not in contact with the oppositemember and where the press-contacting force is therefore not applied tothe sealing material, the straight bottom edge face-contacts with thebottom face of the ant groove.

If the length of the straight bottom edge is enough, the force to fixthe sealing material by the ant groove is larger than the fixation forcebetween the sealing material and the opposite member during the motionof releasing the sealing, so that the sealing material can be preventedwell from slipping out of the ant groove. Though depending on thedemanded sealing function and on the overall sizes of the ant groove andsealing material, the length L0 of the straight bottom edge can be setin the range of L0/Y=0.35-0.6 in relation with the overall width Y ofthe sealing material.

<Arched Convex Edge>:

The arched convex edge contacts with a surface of the other memberopposite to the ant groove, that is, the opposite member. The archedconvex edge is pressed against the opposite member to thus becomeelastically deformed, thereby performing the appropriate sealingfunction.

The shape represented by the term “arched” includes smoothly curved arcshapes, such as oval arc shapes, besides circular arc shapes. Such asthe elastic deformability, the area of contact with the opposite member,and the distribution of contact face pressures vary with the curvatureradius of the place contacting with the opposite member. There can beadopted the same range as of the curvature radius of the place,contacting with the opposite member, of conventional sealing materialsfor ant grooves. When the curvature radius of the arched convex edge inthe place contacting with the opposite member is represented by R1 andwhen the overall height of the sealing material is represented by H,these can be set so as to satisfy R1/H=0.25-0.3, though depending on theoverall size of the sealing material and on the demanded performances.

<First Projecting Edge>:

The first projecting edge connects with one end of the straight bottomedge and projects outside this end portion of the straight bottom edge.In a state fitted to the ant groove, the first projecting edge is seatedin a space which is inside the ant groove, outside the opening of theant groove, and under a sloping face of the ant groove.

The shape of the first projecting edge is free of especial limitation ifits entirety is a convex shape. Specific examples thereof include:curved line shapes such as circular arc shapes; crooked line shapesconsisting of more than one straight line; and combinations of curvedline shapes and straight line shapes. In the case where the firstprojecting edge is arched, its curvature radius R2 can be set in therange of R1/R2=0.95-1.05 in relation with the curvature radius R1 of thearched convex edge. Usually, R1=R2 will do.

The first projecting edge is effective in securing the straight bottomedge in a sufficient length. Even if the sealing material falls intodanger of being drawn out of the ant groove during the motion ofreleasing the sealing, the first projecting edge contacts with a slopingface of the ant groove to thus exercise the resistance force andtherefore plays a part also in preventing the slipping-out of thesealing material.

<Concave Inlet Portion>:

The concave inlet portion is located between the first projecting edgeand the aforementioned arched convex edge. When the sealing material isfitted to the ant groove, the concave inlet portion is disposed on anopening edge of the ant groove to thus serves as the base point when thesealing material is gyratorily pressed into the ant groove.

The shape of the concave inlet portion is free of especial limitation ifsuch a function can be performed. Shapes which conform to the openingedge of the ant groove are adoptable. For example, in the case where theopening edge of the ant groove has an R (roundness), concave circulararc shapes having a curvature radius a little larger than this R.(roundness) are adoptable.

<Second Projecting Edge>:

The second projecting edge connects with the other end of the straightbottom edge and is composed of straight lines that project outside. Itis also the structure for constituting the below-mentioned cornerportion.

The second projecting edge may be either one straight edge extendingobliquely outward from the above end portion of the straight bottom edgeor a combination of at least two straight edges which connect with eachother in a shape crooked in order from the above end portion of thestraight bottom edge. A pair of straight edges, in other words, twostraight edges, can be combined together in a convexly crooked shape,namely, an elbow shape. It is also possible to combine straight edgesdifferent in length or combine straight edges at different crookedangles. Furthermore, a curve portion may partly be included within therange not spoiling the objective functions.

When the sealing material is fitted to the groove, the second projectingedge is disposed inside the ant groove, outside the opening of the antgroove, and below a sloping face of the ant groove. The length of thestraight bottom edge varies with the projection amount of the secondprojecting edge as well as with that of the aforementioned firstprojecting edge to thus enhance the function of preventing theslipping-out from the ant groove.

The corner portions, which are constituted in positions where thestraight edges included in the second projecting edge cross each otherand in positions where the second projecting edge crosses the straightbottom edge and the sloping edge, perform the function of enhancing thefittability to the ant groove or the fixation force to the bottom faceof the ant groove.

In the crossing place between the second projecting edge and thestraight bottom edge, the sloping angle of the second projecting edge tothe straight bottom edge can be set in the range of θ1=30-70°.

<Sloping Edge>:

One end of the sloping edge connects with the opposite end portion ofthe arched convex edge as to the first projecting edge, and the otherend of the sloping edge connects with the second projecting edge, andthe sloping edge is straight.

The sloping edge is desired to connect smoothly with the arched convexedge. As to the second projecting edge, the sloping edge is desired tocross it to thus constitute a corner portion together therewith. Whenthe sealing material is disposed on a flat face, the sloping edge can bemade to possess a sloping angle in the range of θ2=30-45° to a verticaldirection.

The possession of the sloping edge makes it possible to sufficientlysecure the thickness of the sealing material above the second projectingedge. As a result, when the arched convex edge is pressed against theopposite member, the repulsive force is sufficiently generated to thusmake it possible to enhance the contact face pressure. During the motionof releasing the sealing, the portions ranging from the secondprojecting edge to the sloping edge contact with a sloping face of theant groove outside the opening of the ant groove, so that the slopingedge of the sealing material face-contacts with the sloping face of theant groove across the wide range. Thereby the slipping-out of thesealing material can strongly be resisted.

<Corner Portion>:

The corner portion is constituted in the range of from the straightbottom edge via the second projecting edge to the sloping edge. Thecorner portion will do if it exists in at least one place. As the casemay be, it is constituted in more than one place.

The number and positions of the corner portions being disposed vary withthe shape of the second projecting edge. If the lower end of the secondprojecting edge is a straight line, then a corner portion is constitutedbetween the straight bottom edge and the straight line portion of thesecond projecting edge. In the case where the second projecting edge isthe combination of more than one straight line portion in a crookedshape, a corner portion is constituted in each crooked place. If theupper end of the second projecting edge is a straight line, then acorner portion is constituted between the upper end of the secondprojecting edge and the sloping edge.

The corner portion may be a corner portion which refers to a crossing inthe geometric meaning where straight lines cross each other. What hasbeen formed by rounding off a crossing place between straight lines soas to have a small R (roundness) is also included in the conception ofthe corner portion. In cases of industrially produced sealing materials,it often follows that their corner portions substantially have theaforementioned R (roundness). The size of the R (roundness) can be setin the range of 0.1 to 0.5 mm.

The maximum value X of distances of from the corner portion to theconcave inlet portion can be set so as to have a relationship ofX/B=1.00-1.10 with an opening width B of the ant groove. Favorably,X/B=1.01-1.06.

If the number of the corner portions is 1, then the distance over whichthis one corner portion and the concave inlet portion are linkedtogether is the distance X. Hereupon, the distance, over which thecorner portion and the concave inlet portion are linked together, refersto the shortest distance over which their respective shapes are linkedtogether by a straight line in the case where the corner portion has anR (roundness) or where the concave inlet portion is concavely arched. Inthe case where more than one corner portion are present, the longestdistance in comparison between distances over which those cornerportions are linked with the concave inlet portion is taken as thedistance X.

When the sealing material is fitted to the groove, the sealing materialneeds to be elastically deformed in a sealing-material-shrinkingdirection by the degree of the difference between the distance X and theopening width B. Accordingly, the smaller the ratio X/B is, the smallerdeformation amount the fitting is satisfied with and therefore theeasier the fitting becomes. However, in the case where the ratio X/B istoo small, only a small volume is seated inside the ant groove andoutside the opening of the ant groove, so that the length of thestraight bottom edge cannot sufficiently be secured, or that there is atendency for the sealing material to slip out of the ant groove duringthe motion of releasing the sealing.

<Vertical Edge>:

The arched convex edge and the concave inlet portion may connectdirectly with each other. However, the sealing material can furthercomprise a vertical edge connecting the arched convex edge and theconcave inlet portion together.

The vertical edge is an edge which extends in a vertical direction thatcrosses a flat face or the straight bottom edge at right angles in astate where the straight bottom edge of the sealing material is mountedon the above flat face.

The possession of the vertical edge makes it possible to increase thedistance of from the top of the arched convex edge to the straightbottom edge, that is, the overall height of the sealing material, in astate where the first projecting edge and the concave inlet portion areseated inside the ant groove. In the sealed state, it is possible toincrease the compression deformation amount in a direction of the heightof the sealing material to thereby enhance the contact face pressure. Inaddition, the vertical edge plays a part also in making a sufficientclearance between an inner edge of the opening of the ant groove and thesealing material. This prevents a side face of the arched convex edgefrom being damaged or deteriorated in durability due to its contact withan opening edge of the ant groove. Even if, when the motion of openingand shutting the sealed portion, the sealing material becomes deformedin a state where the ant groove side member and the opposite member slipa little on each other in horizontal directions, then the arched convexedge can be prevented from colliding with an opening edge of the antgroove.

<Peripheral Length>:

As to the sealing material which is fitted to the aforementioned antgroove of a ring shape in a ring shape corresponding to theaforementioned ant groove of the ring shape, it is desirable that thefirst projecting edge and the concave inlet portion are located at theouter peripheral side of the ring shape, and that the second projectingedge, the straight sloping edge, and the corner portion are located atthe inner peripheral side of the ring shape.

If the peripheral length of the sealing material having such adisposition structure is adjusted, then the performances of the sealingmaterial can more effectively be exercised.

In cases of uses under vacuum, it is desirable that the peripherallength of the sealing material is made shorter than that of the antgroove. If inner peripheral portions of the sealing material, namely,the sloping edge and the corner portion (which is constituted in aportion of the second projecting edge), are brought into contact withthe inner peripheral side face of the ant groove in a state where thesealing material is fitted to the ant groove, then the ant groove'sinner spaces which open into the chamber's inner spaces decrease, sothat the sealing material becomes suitable as a sealing material forvacuum. As to the sealing material according to the present invention,while on the one hand the structure of the second projecting edgefacilitates the fitting, it also has a tendency toward falling off.However, if the inner diameter of the sealing material is extended inthe fitted state, then the retention force of the sealing material isenhanced. In addition, during the fitting motion, the sealing materialis fitted in the predetermined position and attitude in a state shrunkentoward the inner diameter side immediately after passing through theopening of the ant groove. Therefore, misfitting occurs little.

Furthermore, in the case where the peripheral length of the sealingmaterial is shorter than that of the ant groove, the sealing materialcomes into an extended state to cause its elastic deformation or innerstress, so that the fixation force of the sealing material to the antgroove increases. The concave inlet portion contacts with an openingedge of the ant groove to thus cause engagement of the sealing material,so that the stress is caused concentratedly on the concave inletportion. Thus, problems of deterioration in strength and durability canalso be prevented.

It is desirable that the peripheral length of the sealing material isextended by 1-10% in a state where the sealing material is fitted to theant groove of the ring shape when compared with a free state where noexternal force is applied to the sealing material. Favorably, theperipheral length is extended by 4-6%.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention is more specifically illustrated bythe following examples of some preferred embodiments (modes for carryingout the present invention) while referring to the drawings. However, thepresent invention is not limited to them in any way.

As is shown in FIGS. 1 and 2, the sealing material 30 for an ant grooveapproximately in an inclined heart shape is made of an elasticallydeformable rubber material in its entirety and is a ring shapecontinuing in the sectional shape shown in the drawing figures.Fluororubbers, silicone rubbers, and EPDM type rubbers of about 60 toabout 70 HA in hardness are usable as the rubber material.

The sealing material 30 is fitted to a place where a pair of members 10and 20 are to be sealed. In a surface of a counterpart member 20, an antgroove 12 of a ring shape is formed. The ant groove 12 is in the shapeof a trapezoid which widens in the shape of a taper ranging from theupper end opening to the lower end. The ant groove 12 has right and leftsloping faces and a flat bottom face. The width of the opening isrepresented by B. The opening edges are provided with a small R(roundness). The inner corner portions where the right and left slopingfaces and the bottom face cross each other are also provided with aroundness.

[Overall Fitting Mode]:

FIGS. 9 and 10 illustrate a case where the sealing material 30 has beenincorporated into a sealing plate 10 (which is a sealing member for agate valve of semiconductor production apparatus) as an overall fittingmode of the sealing material 30.

The sealing plate 10 is a rectangular plate shape. The ant groove 12 isdisposed in a rectangular ring shape along the outer periphery of oneface. The sealing material 30 for an ant groove is fitted to this antgroove 12. The opening of the gate valve is sealed by pressing thesealing plate 10 against a valve seat face provided to the outerperiphery of the opening of the gate valve which is the opposite memberto be sealed. By the motion of opening and closing the gate valve, thesealing plate 10 repeats a state of being pressed against the valve seatface to thus seal the joint place and a state of separating from thevalve seat face along with the sealing material 30 fitted to the antgroove 12.

The peripheral length of the sealing material 30 is formed so as to be alittle shorter than that of the ant groove 12. In the state fitted tothe ant groove 12, the sealing material 30 is in a state where itsperipheral length is extended and in a state pressed on the innerperipheral side of the ant groove 12.

[Structure of Sealing Material for Ant Groove]:

The sectional outline shape of the sealing material 30 as illustrated inFIG. 2 is hereinafter explained on the basis of a horizontal line hcorresponding to a bottom face of the ant groove 12 and a vertical linev crossing the horizontal line h at right angles.

The straight bottom edge 34 extends along the horizontal line h and,when fitted to the ant groove 12, contacts with the bottom face of theant groove 12. The length of the straight bottom edge 34 is L0.

On the right and left sides of the straight bottom edge 34, there are afirst projecting edge 33 and a second projecting edge 35, 36.

The first projecting edge 33 is a circular arc shape of R2 in curvatureradius and projects outward from an end portion of the straight bottomedge 34. The upper portion of the first projecting edge 33 connectssmoothly with a concave inlet portion 39 of a small concave circular arcshape. The upper portion of the concave inlet portion 39 connectssmoothly with a vertical edge 32 consisting of a straight line parallelto the vertical line v. The upper portion of the vertical edge 32connects smoothly with an arched convex edge 31 of a circular arc shapeof R1 in curvature radius.

The second projecting edge 35, 36 is composed of two straight edges 35,36. The straight edge 35 extends obliquely outward from an end portionof the straight bottom edge 34. In the crossing place between thestraight bottom edge 34 and the straight edge 35, there exists a cornerportion 37 c. The sloping angle of the straight edge 35 to the straightbottom edge 34 is θ1. In the case of this mode for carrying out thepresent invention, the sloping angle can be set in the range of θ1=about30 to about 40°. The next straight edge 36 having a larger sloping anglethan the straight edge 35 connects with the upper end of the straightedge 35. Also in the crossing place between the straight edges 35 and36, there exists a corner portion 37 b. The upper end of the straightedge 36 connects with a sloping edge 38 which slopes inward. Also in thecrossing place between the straight edge 36 and the sloping edge 38,there exists a corner portion 37 a. The upper end of the sloping edge 38smoothly connects with the arched convex edge 31. The sloping angle ofthe sloping edge 38 to the vertical line v is θ2.

The overall width Y of the sealing material 30 is the distance of fromthe corner portion 37 a (between the straight edge 36 and the slopingedge 38) to the outer peripheral end of the first projecting edge 33.The overall height H of the sealing material 30 is the distance of fromthe straight bottom edge 34 to the upper end of the arched convex edge31. The maximum value X of the distances of from the corner portions 37a, 37 b, and 37 c to the concave inlet portion 39 is the distance X offrom the corner portion 37 b (between the straight edges 35 and 36) tothe concave inlet portion 39.

[Mode of Fitting to Ant Groove]:

The size of each portion in the above sectional outline shape is set sothat such a fitting mode as shown in FIG. 1 can be realized to the antgroove 12 which is to receive the fitting. Specifically, the straightbottom edge 34 contacts with the bottom face of the ant groove 12. Thecorner portion 37 a between the sloping edge 38 and the straight edge 36contacts with the inner peripheral side sloping face of the ant groove12. The entirety of the second projecting edge 35 and 36 projectsoutside the opening of the ant groove 12 and is seated under the slopingface of the ant groove 12. The first projecting edge 33 also projectsoutside the opening of the ant groove 12 and is seated under the slopingface of the ant groove 12. The concave inlet portion 39 is disposed alittle below and a little inside the opening of the ant groove 12 andhas a little clearance between the concave inlet portion 39 and anopening edge. The vertical edge 32 extends from a little inside anopening edge of the ant groove 12 to above this opening edge. The archedconvex edge 31 projects out of the surface of the member 10. The upperend of the arched convex edge 31 faces the surface of the oppositemember 20. The amount of the projection of the arched convex edge 31above the ant groove 12 corresponds to the tightening cost during thesealing.

As is aforementioned, when fitted to the ant groove 12, the sealingmaterial 30 comes into a state where its peripheral length is extended,so that the corner portion 37 a of the sealing material 30 at its innerperipheral side comes into a state pressed against the inner peripheralside sloping face of the ant groove 12, and that the concave inletportion 39 and the vertical edge 32 come into a state apart from theouter peripheral side sloping face and opening edge of the ant groove12.

[Fitting of Sealing Material for Ant Groove]:

FIG. 3 illustrates a fitting motion of the sealing material 30 stepwisewith double-dot chain lines.

First of all, the concave inlet portion 39 of the sealing material 30 ispositioned on an opening edge of the ant groove 12. If the vertical edge32 of the sealing material 30 is slipped in a state touched to theopening edge of the ant groove 12, then the concave inlet portion 39 issurely positioned on the opening edge of the ant groove 12.

If the second projecting edge 35, 36 side is made to gyrate downwardaround the concave inlet portion 39 as the base point, then a part ofthe second projecting edge 35 and 36 hits on an opening edge of the antgroove 12. Specifically, the straight edge 35 near the corner portion 37b hits on this opening edge of the ant groove 12.

The sealing material 30 is made to further gyrate downward to thus pressit into the ant groove 12. While the sealing material 30 getselastically deformed in the periphery of the corner portion 37 b, thecorner portion 37 b passes the above opening edge of the ant groove 12.

If the sealing material 30 passes the above opening edge of the antgroove 12, then thereafter the sealing material 30 migrates downward asit is. And then, if the straight bottom edge 34 of the sealing material30 contacts with the bottom face of the ant groove 12, then the sealingmaterial 30 becomes fitted to the ant groove 12.

In the above fitting motion, an adequate fitted state is surely obtainedby only pressing the sealing material 30 into the ant groove 12 in a wayfor the entire sealing material 30 to gyrate after having positioned theconcave inlet portion 39 by disposing it on an opening edge of the antgroove 12. The concave inlet portion 39 is easy to confirm alsovisually, and its concavity can be confirmed even by the feel obtainedby touching its surface. Therefore, there is almost no possibility ofmaking a mistake in the motion of disposing the concave inlet portion 39on an opening edge of the ant groove 12. If the concave inlet portion 39is utilized as the base point, then the motion of pressing the sealingmaterial 30 into the ant groove 12 can be carried out easily and surely.The elastic deformation of the sealing material 30 during its fitting tothe ant groove 12 will do if it occurs to only a slight portion in theperiphery of the corner potion 37 b. Therefore, the pressing of thesealing material 30 into the ant groove 12 can be achieved by onlyapplying a comparatively weak force. If the corner portion 37 b passesan opening edge of the ant groove 12, then the straight bottom edge ofthe sealing material 30 comes into contact with the bottom face of theant groove 12 naturally as it is without twisting the sealing material30 or much changing its attitude inside the ant groove 12, so that thesealing material 30 is fitted in the predetermined position andattitude.

In such a way, the fitting motion is easy. Therefore, there is a meritsuch that it is not necessary to specify the size tolerance so muchstrictly during the production of the sealing material 30. Even if thesize of the sealing material 30 is a little too large, there is nopossibility that the motion of pressing it into the ant groove 12 isdifficult. Even if the size of the sealing material 30 is a little toosmall, then, in a state fitted to the ant groove 12, the firstprojecting edge 33 and the second projecting edge 35, 36 project outsidethe opening of the ant groove 12 to thus surely prevent the sealingmaterial 30 from falling off from the ant groove 12. In a state fittedinside the ant groove 12, the straight bottom edge 34 contacts with thebottom face of the ant groove 12 across a wide area to thereby enablegood prevention of such as tumbling, attitudinal variation, andpositional deflection.

<Detection of Misfitting>:

As to the sealing material 30 according to the present invention, itsadequate fitted state can be obtained easily and surely without needingany special technique. However, as the case may be, misfitting is causedby such as making a mistake in the operational procedure.

For example, as is illustrated in FIG. 4, as the case may be, for thecause such that the concave inlet portion 39 of the sealing material 30is not brought into precise contact with an opening edge of the antgroove 12, the concave inlet portion 39 unfavorably falls into the antgroove 12 before the entirety of the sealing material 30 enterssufficiently the inside of the ant groove 12. The first projecting edge33 hits on the bottom face of the ant groove 12 earlier than thestraight bottom edge 34. In this state, however strongly the sealingmaterial 30 may be pressed into the ant groove 12, it is impossible tocarry out the pressing any more. There is a worry that, in this stagewhen it has become impossible to press the sealing material 30 into theant groove 12, the fitting may be wrongly recognized to have properlybeen completed.

However, in such a misfitted state, the corner portion 37 b in themiddle of the second projecting edge 35 and 36 and the corner portion 37a between the sloping edge 38 and the straight edge 36 of the secondprojecting edge result in remaining exposed above the ant groove 12. Thecorner portions 37 a and 37 b can be confirmed visually as ridgelinesdistinctly different from their peripheral curved faces and flat faces.Even if the sealing material 30 is such as black and is therefore in astate where it is difficult to distinguish differences between faces,the ridgelines where faces cross each other can be confirmed distinctlyby the eye. In addition, if a finger is touched to the sealing material30 along its surface outside the ant groove 12, then the ridgelineportions give a feel different distinctly from their peripheries.

From such differences in external appearance or feel, the misfitting caneasily be discovered. As a result, there is reduced a problem such thatsuch as unsatisfactory sealing or damage to the sealing material 30 iscaused by the use without noticing the misfitting.

[Sealing Function of Sealing Material for Ant Groove]:

As is illustrated in FIG. 5, the opposite member 20 comes into contactwith the upper portion of the sealing material 30 fitted to the antgroove 12. The opposite member 20 contacts with the top of the archedconvex edge 31 of the sealing material 30 and then presses it downward.The press force transmitted downward from the arched convex edge 31deforms elastically the entirety of the sealing material 30. Therepulsive force of the elastically deformed sealing material 30 causes ahigh contact face pressure in the contact range L2 between the sealingmaterial 30 and the opposite member 20, so that the contact range L2 issealed. Because the straight bottom edge 34 of the sealing material 30is also pressed against the bottom face of the ant groove 12, a highcontact face pressure occurs also in the contact range L1 between them,so that the sealing is made.

Incidentally, inside the ant groove 12, the sealing material 30 becomesdeformed so as to expand right and left sideward. As a result, thecircular-arc-shaped first projecting edge 33 becomes deformed so as tocontact with the range of from the bottom face to sloping face of theant groove 12. The shape ranging from the arched convex edge 31 via thevertical edge 32 to the concave inlet portion 39 also becomes deformedso as to be compressed upward and downward and to expand sideward. As tothe arched convex edge 31, its upper end face becomes flat. However,some degree of clearance is maintained between the vertical edge 32 andan opening edge of the ant groove 12.

The straight edges 35, 36 of the second projecting edge and the slopingedge 38 also become deformed along a sloping face of the ant groove 12from its bottom face. The sloping edge 38 face-contacts with the slopingface of the ant groove 12 across the wide range from the upper straightedge 36. This contact range also contributes to the sealing function. Apart of the lower straight edge 35 is disposed in the form of obliquelytraversing an inner corner portion of the ant groove 12.

When the length of the contact range L2 between the sealing material 30and the opposite member 20 on the upper end side of the sealing material30 is compared with the length of the contact range L1 between thesealing material 30 and the bottom face of the ant groove 12 on thelower end side of the sealing material 30, then L1>L2 is satisfied. Thefixation force between the ant groove 12 and the sealing material 30 islarger than the fixation force between the sealing material 30 and theopposite member 20.

<Contact Face Pressure>:

FIG. 6 shows a distribution graph of contact face pressures acting onthe sealing material 30. Shown are contact face pressures in the contactrange L1 between the sealing material 30 and the bottom face of the antgroove 12 on the bottom face side of the sealing material 30 and contactface pressures in the contact range L2 between the sealing material 30and the surface of the opposite member 20 on the top face side of thesealing material 30.

First of all, an explanation is given below about the bottom face side(ant groove bottom face side) of the sealing material 30.

In FIG. 5, the origin of the graph corresponds to the left end of thecontact range L1 between the sealing material 30 and the bottom face ofthe ant groove 12. The contact face pressure rapidly rises from thisorigin and then leads to a sharp-pointed peak P1. This rising line iscaused by the elastic repulsive force of the portions, ranging from thesecond projecting edge 35, 36 to the sloping edge 38, of the sealingmaterial 30. The peak point P1 is a position corresponding to the cornerportion 37 c between the straight bottom edge 34 and the secondprojecting edge 35. It can be inferred that, in such a position wherethe shape varies intermittently, the contact face pressure becomesmaximized for the cause such that the stress concentrates.

Beyond the aforementioned peak P1, the contact face pressure decreases.However, after having decreased a little, the contact face pressure doesnot vary so much in the range corresponding to the straight bottom edge34 of the sealing material 30.

Also in the range of from the straight bottom edge 34 via the firstprojecting edge 33 to an end portion of the contact range L1, there is apeak P2 of a rise of the contact face pressure. However, the peak P2 inthis portion is a peak P2 which is lower than the aforementioned peak P1and is dull-pointed and gentle. Its cause can be inferred as follows:because the shape smoothly varies in the range of from the straightbottom edge 34 to the first projecting edge 33, the stress does notconcentrate so extremely much, and the contact face pressure variescomparatively gently. The thickness of the sealing material 30 islessened correspondingly to the presence of the concave inlet portion 39above the first projecting edge 33, and this also can be considered tobe a cause that the height of the peak P2 is lower than that of the peakP1.

In the case where there is possessed such a contact face pressuredistribution, it follows that the high contact face pressure at theaforementioned sharp-pointed peak P1 enhances greatly the sealingfunction between the sealing material 30 and the bottom face of the antgroove 12. Also, because the sealing material 30 comes into a statestrongly fixed to the bottom face of the ant groove 12, there isenhanced the function of preventing the sealing material 30 fromfloating up from the ant groove 12 during the motion of releasing thesealing.

Next, an explanation is given below about the top face side (oppositemember side) of the sealing material 30.

In FIG. 5, the origin of the graph corresponds to the left end of thecontact range L2 between the sealing material 30 and the surface of theopposite member 20. The contact face pressure draws a parabola havingits peak at the tip end of the arched convex edge 31. The contact facepressure continuously decreases both sideward from this peak.

[Prevention of Slipping-Out of Sealing Material for Ant Groove]:

As is illustrated in FIG. 7, such as when the gate valve is opened, theopposite member 20 is separated from the member 10 having the ant groove12.

Between the sealing material 30 and the opposite member 20 which werepressed against each other by high contact face pressure and between thesealing material 30 and the ant groove 12 which were pressed againsteach other by high contact face pressure, there occur fixation rangesL2′ and L1′ respectively where they have been fixed to each other.

If the opposite member 20 is separated in this state, the sealingmaterial 30 becomes deformed so as to be extended between the range L2′of the fixation to the opposite member 20 and between the range L1′ ofthe fixation to the bottom face of the ant groove 12. Either smaller onein fixation force of the upper and lower fixation ranges L2′ and L1′becomes peeled off earlier than the other.

Properly, the fixation range L2′ between the opposite member 20 and thesealing material 30 is peeled off, so that the sealing material 30 isleft behind remaining fitted to the ant groove 12, and that only theopposite member 20 goes away.

However, if the fixation force between the sealing material 30 and thebottom face of the ant groove 12 is weak, then there occurs a problemsuch that the fixation range L1′ between the sealing material 30 and thebottom face of the ant groove 12 is peeled off earlier and, as a result,the sealing material 30 is unfavorably slipped out of the ant groove 12in a state attached to the opposite member 20.

Particularly, if the motion of separating the opposite member 20 is madein a tilted state or in such a form as slid, then, as the case may be,the sealing material 30 and the bottom face of the ant groove 12 areearlier peeled off from each other even though the fixation forcebetween the sealing material 30 and the bottom face of the ant groove 12is strong in some degree.

As is aforementioned, in the above mode for carrying out the presentinvention, the fixation range L1′ between the bottom face of the antgroove 12 and the sealing material 30 has, at both ends of this fixationrange, the peaks P1 and P2 of the contact face pressure. Therefore, thefixation force between the sealing material 30 and the ant groove 12 isso high that they are not easily peeled off from each other. For thesealing material 30 to be peeled off from the bottom face of the antgroove 12, naturally, the peeling-off must make progress gradually fromboth ends of the fixation range to its center. However, because thepeaks where the contact face pressure is high are present at both ends,the peeling-off does not make progress toward the center side unless apeeling-off force stronger than the fixation force at the above peakpoint P1 or P2 is applied.

On the other hand, in the fixation range L2 between the sealing material30 and the opposite member 20, the contact face pressure acting betweenthe arched convex edge 31 of the sealing material 30 and the oppositemember 20 is parabolic. Therefore, also as to the fixation force, itpeaks at the top of the arched convex edge 31 and becomes weaker gentlyboth sideward. The peeling-off force acts on the weak portions at bothends of the fixation range to thus peel off the sealing material 30 andthe opposite member 20 from each other and then gradually acts towardthe center, so that the entirety of the fixation range becomes peeledoff easily.

As a result of the above, the sealing material 30 involves an extremelygreat difference between the fixability to the opposite member 20 on theupper end side and the fixability to the bottom face of the ant groove12 on the lower end side. Therefore, the sealing material 30 and theopposite member 20 easily peel off from each other, so that the sealingmaterial 30 can maintain an appropriate fitted state seated in the antgroove 12.

Furthermore, in FIG. 7, the sloping edge 38 of the sealing material 30comes into contact with a sloping face of the ant groove 12 across awide range along this sloping face, and the resistance acting due tothis contact also effectively performs the function of preventing thesealing material 30 from slipping out of the ant groove 12.

[Another Mode, Different as to Sectional Shape, for Carrying Out thePresent Invention]:

The sealing material 30 for an ant groove, which is a mode illustratedin FIG. 8 for carrying out the present invention, is common to theaforementioned mode for carrying out the present invention as to basicstructure, but is different therefrom partly as to shape. Differentpoints are mainly explained below.

Only one straight edge 35 is provided as the second projecting edgewhich connects the straight bottom edge 34 and the sloping edge 38together. The corner portions 37 a and 37 c are constituted at both endsof the straight edge 35. The sloping angle θ1 between the straightbottom edge 34 and the straight edge 35 in this mode for carrying outthe present invention is set at an angle which is a little larger thanthat in the mode for carrying out the present invention such as FIG. 2in which the second projecting edge is composed of two straight edges 35and 36. The maximum value X of distances over which the concave inletportion 39 and the second projecting edge 35 are linked together is thedistance of from the concave inlet portion 39 to the corner portion 37 aor 37 c. When the sealing material 30 is fitted to the ant groove 12,the elastic deformation of the sealing material 30 becomes needed in aperiod when the corner portion 37 c or corner portion 37 a passesthrough the opening of the ant groove 12. In both periods, thedeformation can be made by comparatively small force. In such amisfitting case as illustrated in FIG. 4, the corner portion 37 a stillresults in remaining exposed outside the ant groove 12, and thereforethe misfitting can easily be detected.

The first projecting edge 33 is a circular arc shape in its entirety andhas a straight edge 33 a as a portion connecting with an end portion ofthe straight bottom edge 34. Accordingly, it follows that, also at theboundary between the straight bottom edge 34 and the first projectingedge 33, there is a corner portion. In such a shape, the contact facepressure distribution as illustrated in FIG. 6 results in indicatingsharp-pointed high peaks at both ends of the straight bottom edge 34. Asa result, the sealing function between the sealing material 30 and thebottom face of the ant groove 12 is enhanced, and the fixation forcetherebetween also increases, and the slipping of the sealing material 30out of the ant groove 12 due to the motion of releasing the sealing isalso well prevented.

INDUSTRIAL APPLICATION

The sealing material according to the present invention for an antgroove can be fitted to the ant groove extremely easily in a properattitude by pressing the sealing material into the ant groove in a wayfor the second projecting edge side to gyrate in a state where theconcave inlet portion of the sectional shape of the sealing material isdisposed on an opening edge of the ant groove. Particularly, at thesecond projecting edge side, if locally only the neighborhood of thecorner portion is elastically deformed, then the sealing material caneasily be pressed into the ant groove even without deforming the widerange of the sealing material, so the fitting operation becomes veryeasy. For uses such as gate valves of semiconductor apparatus which needa periodic exchange of sealing materials for ant grooves, thestreamlining of the fitting operation and the reliability of the fittingare extremely useful in practical value.

In addition, because the straight bottom edge contacts with the bottomface of the ant groove across the wide range and because the repulsiveforce is generated when the shape of such as the sloping edge and thesecond projecting edge is elastically deformed, a strong contact facepressure can be generated at the bottom face of the ant groove. As aresult, the sealing function can be enhanced, and the fixation force ofthe sealing material to the bottom face of the ant groove increases.

Particularly, near the corner portion between the straight bottom edgeand the second projecting edge, an extremely high peak of the contactface pressure occurs to thus exercise the fixation force which acts asthe strong resistance to the force of peeling off the sealing materialfrom the bottom face of the ant groove. As a result, there is solved theproblem such that the sealing material unfavorably slips out of the antgroove in the form of remaining fixing to the opposite member during themotion of releasing the sealing.

The ant groove is substantially trapezoidal shape in section, with theant groove having an opening and a bottom opposite the opening, with theopening having a length running transversely to the sealing material,with the bottom having a length running transversely to the sealingmaterial, and with the length of the bottom being greater than thelength of the opening such that said ant groove is dovetail shaped insection.

1. A sealing material for an ant groove that is fitted to the ant groove made in a surface of either one of a pair of members, that is in a joint place between these members and that makes contact with a surface of the member facing the ant groove, thereby sealing both of the members, with the sealing material comprising: an elastically deformable material; and a sectional shape having: a straight bottom edge which is disposed on a bottom face of said ant groove, with said straight bottom edge having a first end and a second end; an arched convex edge which makes contact with the surface of said member facing said ant groove; a first projecting edge which connects with said first end of said straight bottom edge and projects obliquely outside from said first end of said straight bottom edge; a concave inlet portion which is located between said first projecting edge and said arched convex edge; a second projecting edge which connects with the second end of said straight bottom edge and is composed of straight lines, with the second projecting edge projecting obliquely outside from said second end of said straight bottom edge; a straight sloping edge of which one end connects directly with an end of said arched convex edge that is opposite to said first projecting edge and of which the other end connects directly with said second projecting edge; and a corner portion which is found in a connecting portion of said second projecting edge and said straight sloping edge; wherein: when the sealing material for the ant groove is fitted to said ant groove, said concave inlet portion is disposed on an opening edge of the ant groove, and then an entirety of the sealing material for the ant groove is made to gyrate toward an inside of the ant groove around said concave inlet portion as a base point, so that the sealing material for the ant groove gets pressed into the ant groove in a state where a periphery of said corner portion is elastically deformed.
 2. A sealing material for an ant groove according to claim 1, wherein a maximum value X of distances of from said corner portion to said concave inlet portion has a relationship of X/B=1.001-1.10 with an opening width B of said ant groove.
 3. A sealing material for an ant groove according to claim 1 or 2, wherein: said second projecting edge is formed by connecting a pair of straight edges together at an angle; and another corner portion is disposed between said straight bottom edge and said second projecting edge; and still another corner portion is disposed between said pair of straight edges at an elbow place of said second projecting edge.
 4. A sealing material for an ant groove according to claim 3, which: further comprises a vertical edge connecting said arched convex edge and said concave inlet portion together; and makes a clearance between said vertical edge and an opening edge of said ant groove when fitted to said ant groove.
 5. A sealing material for an ant groove according to any one of claims 1 and 2, which: further comprises a vertical edge connecting said arched convex edge and said concave inlet portion together; and makes a clearance between said vertical edge and an opening edge of said ant groove when fitted to said ant groove.
 6. A sealing material for an ant groove according to claim 1, wherein said ant groove is formed into a ring shape, and said sealing material is formed into a ring shape corresponding to said ring shaped ant groove, and is fitted to said ring shaped ant groove, with said ring shape having an outer peripheral side and an inner peripheral side, with the sealing material comprising: a structure such that said first projecting edge and said concave inlet portion are located at the outer peripheral side of said ring shape; a structure such that said second projecting edge, said straight sloping edge, and said corner portion are located at the inner peripheral side of said ring shape; and a peripheral length extended by 1-10% in a state fitted to said ant groove of the ring shape when compared with a free state of said sealing material.
 7. A sealing material according to either of claim 1 or 2 and in combination with said ant groove, wherein said ant groove comprises a substantially trapezoidal shape in section, with the ant groove having an opening and a bottom opposite the opening, with the opening having a length running transversely to the sealing material, with the bottom having a length running transversely to the sealing material, and with the length of the bottom being greater than the length of the opening such that said ant groove is dovetail shaped in section.
 8. A sealing material for an ant groove that is fitted to the ant groove made in a surface of either one of a pair of members, that is in a joint place between these members and that makes contact with a surface of the member facing the ant groove, thereby sealing both of the members, with the sealing material comprising: an elastically deformable material; and a sectional shape having: a straight bottom edge which is disposed on a bottom face of said ant groove, with said straight bottom edge having a first end and a second end; an arched convex edge which makes contact with the surface of said member facing said ant groove; a first projecting edge which connects with said first end of said straight bottom edge and projects obliquely outside directly from said first end of said straight bottom edge, with the first projecting edge being one of a) a convex edge; and b) a combination of a convex edge and a straight edge; a concave inlet portion which is located between said first projecting edge and said arched convex edge; a second projecting edge which connects with the second end of said straight bottom edge and is composed of straight lines, with the second projecting edge projecting obliquely outside directly from said second end of said straight bottom edge; a straight sloping edge of which one end connects directly with an end of said arched convex edge that is opposite to said first projecting edge and of which the other end connects directly with said second projecting edge; and at least one corner portion which is found in a range that extends from said straight bottom edge via said second projecting edge to said straight sloping edge; wherein: when the sealing material for the ant groove is fitted to said ant groove, said concave inlet portion is disposed on an opening edge of the ant groove, and then an entirety of the sealing material for the ant groove is made to gyrate toward an inside of the ant groove around said concave inlet portion as a base point, so that the sealing material for the ant groove gets pressed into the ant groove in a state where a periphery of said corner portion is elastically deformed.
 9. A sealing material for an ant groove that is fitted to the ant groove made in a surface of either one of a pair of members, that is in a joint place between these members and that makes contact with a surface of the member facing the ant groove, thereby sealing both of the members, with the sealing material comprising: an elastically deformable material; and a sectional shape having: a straight bottom edge which is disposed on a bottom face of said ant groove, with said straight bottom edge having a first end and a second end; an arched convex edge which makes contact with the surface of said member facing said ant groove; a first projecting edge which connects with said first end of said straight bottom edge and projects obliquely outside directly from said first end of said straight bottom edge; a concave inlet portion which is located between said first projecting edge and said arched convex edge; a second projecting edge which connects with the second end of said straight bottom edge and projects obliquely outside directly from said second end of said straight bottom edge, with the second projection edge being one of a) a straight edge; and b) a combination of a pair of straight edges set at an angle to each other; a straight sloping edge of which one end connects directly with an end of said arched convex edge that is opposite to said first projecting edge and of which the other end connects directly with said second projecting edge; and at least one corner portion which is found in a range that extends from said straight bottom edge via said second projecting edge to said straight sloping edge; wherein: when the sealing material for the ant groove is fitted to said ant groove, said concave inlet portion is disposed on an opening edge of the ant groove, and then an entirety of the sealing material for the ant groove is made to gyrate toward an inside of the ant groove around said concave inlet portion as a base point, so that the sealing material for the ant groove gets pressed into the ant groove in a state where a periphery of said corner portion is elastically deformed. 